Control modules are implemented in a variety of systems to process data and provide control signals. For example, vehicle control modules generate control signals that direct the operation of vehicle components. The control module receives signals from various sensors and other devices that monitor operating characteristics (e.g., engine speed, temperature, pressure, gear ratio and the like). The control signals are based on the signals received from the various sensors. More particularly, the control module processes signal information using an arithmetic logic unit (ALU). The control module processes the control signals based on a pre-programmed control strategy.
In some applications, control modules generate safety critical control signals. That is to say, the control signals direct component operation that can effect vehicle performance. For example, in a vehicle having a shift-by-wire system, the control module generates control signals that regulate shifting of a transmission. Inaccuracy in the control signals can result in damage to the components of the transmission and/or improper operation of the transmission.
A defective ALU and/or memory registers can effect control signal accuracy. Therefore, integrity checks have been developed to determine whether the ALU and/or memory registers are functioning properly. Traditional ALU integrity checks, however, fail to check all operations that the ALU performs.